“We know classroom teachers face false allegations of assault from pupils and searches mean they can be put in a vulnerable situation. Teachers need the training to enable them to exercise this right confidently.”

At the moment, all primary and secondary schools can search pupils for knives and other weapons by patting down their clothing and screening them using airport-style metal detectors.

They can also ask pupils suspected of bringing banned items into school to turn out pockets or open bags. But only police can frisk children for drugs or other items and teachers are expected to call the local force if searches are needed.

“Low level behavioural problems can sometimes be a forerunner to more serious issues and I want to help schools step in early to prevent problems further down the line," Mr Balls said.

“We need to ensure schools have the powers and support they need to maintain good behaviour and to stop problems in the wider community, such as drugs and alcohol use, entering the school grounds.”

The powers are set out in the Apprenticeships, Skills, Children and Learning Act 2009.

It also requires schools to record and report “significant incidents” in which staff have used forced to restrain a pupil.

All schools must also join new-style “behaviour partnerships” – groups of local secondaries sharing resources to crackdown on unruly pupils.

Controversially, it forces schools to share expelled children to ensure the worst-behaved pupils are not concentrated in one place.

The move has been criticised by the Conservatives who claim it risks undermining headteachers’ authority.

The Act also reforms the way schools are inspected by Ofsted. At the moment, most schools in England are inspected every three or four years.

But under the Act, the best schools will be left for up to six years while those considered to be struggling will be vetted annually.